Fan



C. E. JACOBS.

FAN.

APPLICATION FILED JULY 25. 1921.

Patented Jan. 24, 1922.

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ATTORNEY.

. 0 E. JACOBS.

I FAN.

APPLICATION FILED JULY 25, I921-f Patented Jan. 24,1922.

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CLARENCE E. JACOBS, OF DETROIT, MICHIGAN.

FAN.

Specification of Letters Patent.

Patented Jan. 24, 1922.

Application filed July 25, 1921. Serial No. 487,489.

a citizen ofthe United States, and residing at Detroit, in the county ofWayne and State of Michigan, haveinvented a new and Improved Fan, ofwhich the following is a specification.

This invention relates to the construction of metal fans especiallyadapted for forcing currents of air to pass through the radiators ofmotor vehicles and wherever else currents of vapors or gases are to bemoved, and its object is to provide a simple and effective structure ofthis character which will have great strength and which will be so stiffthat it will have little vibration and therefore cause a minimum ofhumming or singing noise. Y

This invention consists of a pair of twoblade members having fiat hubsunited together so that the blades are evenly spaced, the blades beingtwisted adjacent the hubs to give them the proper pitch, the metal atthe edges of the twisted portions being stretched and-arched to give theblades great stiffness.

It further consists in securing a reinforcing spider to the middleportions of the blade members and in forming this spider with archedribs to secure greater stiffness.

It also consists in the details of construction illustrated in theaccompanying drawparticularly pointed out in the fan adapted to besecured by means of six screws. Figs. 7 and 8 are elevations of twomodified forms of this fan.

Similar reference characters refer to like parts throughout the severalviews.

It has been found that at certain critical speeds fans formed of stripsof sheet metal united at their middle portions are very liable to giveout a more or less sustained,

note because of the vibrations of the ends of the blades.' This isespecially the case where the blades are narrow next to the hubs, beingcut away at this -polnt so that they may be easily bent to give theblade proper pitch. I have found that by making these blades of unusualwidth and stiffness at the hub, the vibrations of the ends of thebladesare substantially eliminated and the tendency of the blades to changetheir pitch is entirely obviated.

The fan shown in Figs. 1 to 6 of the drawin is formed of two blademembers and a spider. The blank for the blade members is shown in Fig. 4and consists of the two blade portions 1 and the hub portion 2,thelatter having ears 3 and holes 4 for the bolts or screws by means ofwhich the fan is connected to the shaft or other device by which it issupported. If desired, ribs 5 may be embossed on these blade members asindicated in Fig. 4. z

The spider blank consists of a central hub portion 6 and the radial arms7, each preferably formed with an embossed rib 8. It also has four holes9 correspondin to the holes 4 in the blade members. hen the fan is to beassembled, the two blade members are placed upon a stationary die havingat least two upwardly extendingpins which extend through the holes 4 andthe movable die is brought down onto the two blade members, bending themto the desired shape.

When the blades are bent, the metal at the points 10 and 11 at each sideof the central line of each blade adjacent the hub is sharply stretchedand bent, up at one side and down at the other, forming arches whichgive great stiffness to the metal at these points and which cannot bereturned to their original form except by pressure greater than thatwhich can ever be exerted on the blades by the air through which theymove. The ears 3 on the hubs of the blade members are bent up into thecups formed by this distortion of the metal, as shown in Figs.- 2 and 5.

After the first stroke of the die I prefer to position the spider on theblade members and bring the movable die down again onto the three partsto cause all three members to fit each other. Thereafter the spider maybe united to the blade members by spot welding at the points.14.- and byrivets 15 at the ends of the arms if desired. I prefer to spot weld theears 3 on the hub of each blade member to the other blade member beforeattaching them to the spider;

In Fig. 6 I' have shown a spider with the hub portion 18 and arms 7 andsix holes .20

to receive the screws which secure thefan in' position. The ribs 22 areslightl different from those shown in Fig. 3. f desired, a sphericalcentral boss 23 may be formed on the spider and 'corresponding bosses 24on the blade members.

In Fig. 7 I have shown two blade members secured together by rivets 28passin through holes in the ears 3 and the centra portions of the blades2 which may also be secured together by spot welding at the points 29.The metal of the blades at the points 10 and 11 at each side of thecentral line of each blade adjacent the hub is sharply stretched andbent to give the blade the proper inclination. T e ears 3 of each bladeare bent to fit in the grooves and over the ribs-5 of the other blades.

Where a two bladed fan is desired, it may be constructed as shown inFig. 8. Here again the blades are bent and stretched at the points and11. The spider 30 has arms 31' provided with stiffening ribs 32 whichmay be secured to the blade member by spot welding at the points 33.

The proportions of the various parts and the formofthe ,fan blades andspider may all be changed by those skilled in 'the art without departingfrom the spirit of my invention as set forth in the. following claims. Iclaim: v: 1. In a fan, the combination of a plurality of blade members,each consisting of a hub and two blades, the hubs of the two membersbeing united and the blades twisted adjacent the hubs to give the bladesthe proper pitch and to arch and stretch the metal adacent the hubs ateach side of the central lines of the blades.

2. In a fan, the combination of a plurality of blade members, eachconsisting of a hub and two blades, the hubs of the two members If beingunited and the blades twisted adjacent the hubs to give the blades theproper pitch and to arch and stretch the metalv adjacent the hubs ateach side of the central lines of the blades, and a spider consistingofa hub'and arms extending along and fitting against and secured to saidblades.

3. In a fan, the combination of a plurality of blade members, eachconsisting of a hub and two blades,the hubs of the two members beingunited and the blades twisted adjacent the hubs to give the blades theproperpitch and to arch and stretch the metal adjacent the'hubs at eachside of the central lines of the blades, and a spider consisting of ahub and arms extending along and fitting against and secured to saidblades and having each arm formed with a longitudinal stiffening rib,the hubs of each blade member having ears which are attached to theadjacent blades of the-other member.

.4. A fancomprising a blade member consisting. of a hub and two bladestwisted adjacent the hub to give the blades the proper pitch and to archand stretch the adjacent the hub at each side of the central lines ofthe blades, and a reinforcing member attached to the blade member andconsisting of a hub and an arm fitting against each blade. r y

CLARENCE E. JACOBS.

